Attenuation-Emission Alignment in Cardiac PET/CT with Consistency Conditions

Misaligned attenuation correction factors lead to artifacts and quantitative errors in cardiac PET images, potentially resulting in inaccurate interpretation and/or incorrect clinical decisions. Artifacts from misaligned attenuation-emission scans are common with conventional PET imaging. The potential for misalignment/artifacts is further increased in dual modality PET/CT systems since CT images a snapshot of the respiratory cycle and PET images multiple respiratory cycles. In this work, we developed and tested a method for automated alignment of attenuation and emission data. The alignment process enforces the Radon consistency conditions on the emission data and is derived from previous work by Welch et al. The attenuation image volume is aligned through simple rigid body transformations with the emission data. We test the process with simulated data and measured patient data from two ammonia cardiac PET/CT exams.